Sensor apparatus

ABSTRACT

A sensor apparatus and method for detecting an environmental factor is shown and which includes an acoustic device which has a characteristic resonant vibrational frequency and mode pattern when exposed to a source of acoustic energy, and which further, when exposed to an environmental factor, produces a different resonant vibrational frequency and/or mode pattern when exposed to the same source of acoustic energy.

GOVERNMENT RIGHTS

The United States Government has certain rights in this inventionpursuant to Contract No. DE-AC07-05ID14517 between the United StatesDepartment of Energy and Battelle Energy Alliance, LLC.

TECHNICAL FIELD

The present invention relates to a sensor apparatus and a method fordetecting environmental factors, and more specifically, to an acousticdevice which produces different resonant vibrational frequencies and/ormodal patterns following exposure of the acoustic device to a givenenvironmental factor, and to an arrangement which is operable forreading out an array of such acoustic device sensors.

BACKGROUND OF THE INVENTION

The prior art is replete with numerous examples of material inspectionsystems and other devices such as seen in U.S. Pat. Nos. 6,134,006,6,175,411, 6,401,540, 6,486,962, and 6,836,336 and which are useful forimaging traveling or resonant waves in a medium. Heretofore, thesedevices have been used to investigate the microstructural form andcomposition of an object. Further, many manufactures have begunmanufacturing and marketing various “microassay kits” which are utilizedto detect various materials, including chemicals and biologicalorganisms. These microassay kits, as a general matter, can usually berapidly processed, and permit the use of smaller quantities of analytesin the processing of same. A further parallel effort has been undertakento provide arrays of micro-sensors that can rapidly detect the presenceof a wide range of analytes. An example of this type of approach is the“lab on a chip” approach. These devices, after use, are often read outor interpreted by using a microscope. Typically, a color change in thedevice will indicate the presence of a substance or organism to bedetected. This method can be implemented manually or by an automatedimage analysis.

As the size and complexity of these prior art arrays increase, theproblems of accurately reading the data produced from these complexarrays has become increasingly difficult. Furthermore, in thefabrication of the micro-sensor arrays which utilize various electronicsensors, the ability to accurately read or gather a useful and accurateelectrical output from the various electric sensors becomes increasinglydifficult as the electrical wiring density increases. As could beexpected, an increased wire density leads to “cross talk” betweenadjacent electrical conductors that may be coupled to differentelectrical sensors in the same array.

A sensor apparatus and method for detecting various environmentalfactors which avoids the shortcomings attendant with the prior artpractices utilized heretofore is the subject matter of the presentapplication.

SUMMARY OF THE INVENTION

Therefore, one aspect of the present invention relates to a sensorapparatus which includes an acoustic device which has a characteristicresonant vibrational frequency and mode pattern when exposed to a sourceof acoustic energy, and which further, when exposed to an environmentalfactor, produces a different resonant vibrational frequency and/or modepattern when exposed to the same source of acoustic energy.

Another aspect of the present invention is to provide an array whichincludes a plurality of acoustic devices which are operable to changetheir respective acoustic response when exposed to an environmentalfactor, and an imaging assembly associated with the array of acousticdevices and which is useful in reading, measuring, or otherwisedetecting changes in the acoustic response of the plurality of therespective acoustic devices after they have been exposed to theenvironmental factor.

Another aspect of the present invention relates to a sensor apparatuswhich includes an acoustic device which has a characteristic resonantvibrational frequency, and mode pattern, when exposed to acousticenergy; an assembly for transmitting acoustic energy to the acousticdevice; a source of acoustic energy of a given frequency which issupplied to the acoustic device; and an assembly for imaging theacoustic device to determine the resonant vibrational frequency and/ormodal pattern of the acoustic device when the acoustic device is exposedto the source of acoustic energy.

Still further, another aspect of the present invention relates to amethod for detecting an environmental factor which includes the steps ofproviding an acoustic device having an acoustic property which includesa characteristic resonant vibrational frequency and mode pattern whenexposed to acoustic energy; exposing the acoustic device to anenvironment which has an environmental factor to be detected, andwherein the acoustic property of the acoustic device changes followingthe exposure of the acoustic device to the environmental factor;supplying a source of acoustic energy to the acoustic device; imagingthe acoustic device following exposure of the acoustic device to theenvironmental factor and while supplying the source of acoustic energyto the acoustic device; and determining whether the resonant frequencyand mode pattern of the acoustic device has changed as a result ofexposure to the environmental factor.

These and other aspects of the present invention will be described ingreater detail hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention are described below withreference to the following accompanying drawings.

FIG. 1 is a greatly simplified depiction of a first form of a sensorapparatus of the present invention.

FIG. 2 is a greatly simplified, graphical depiction of a second form ofa sensor apparatus of the present invention.

FIG. 3 is a plan view of the second form of the sensor apparatus as seenin FIG. 2.

FIG. 4 is a plan view of a third form of a sensor apparatus of thepresent invention.

FIG. 5 is a greatly simplified, and enlarged view of a portion of thethird form of the sensor apparatus as seen in FIG. 5.

FIG. 6 is a perspective, greatly enlarged view of a portion of thesensor apparatus as seen in FIG. 5, and which shows the response of thethird form of the sensor apparatus after being exposed to anenvironmental factor.

FIG. 7A is a depiction of a pair of sensors having a thin film bulkresonator design and which illustrates the mode pattern displayed by therespective sensor when exposed to acoustic energy having a frequency of21.006467 MHz, and before exposure to an environmental factor to bedetected.

FIG. 7B is a depiction of the same pair of resonators as seen in FIG.7A, but illustrating the mode pattern displayed by each when exposed toacoustic energy having a frequency of 21.006200 MHz, and followingexposure to an environmental factor to be detected.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

This disclosure of the invention is submitted in furtherance of theconstitutional purposes of the U.S. Patent Laws “to promote the progressof science and useful arts” (Article 1, Section 8).

The sensor apparatus of the present invention and the methodology fordetecting an environmental factor is best understood by the numeral 10in FIG. 1 and following. As seen therein, the sensor apparatus 10 hasfirst, second and third forms which are generally indicated by thenumerals 11, 12 and 13. Referring now to FIG. 1, it will be seen thatthe sensor apparatus 10 has an underlying supporting surface orsubstrate 14 which has an upwardly facing surface 15. Mounted on theupwardly facing surface are a plurality of acoustic devices heredepicted as consecutive rows of individual cantilevered members whichare generally indicated by the numeral 20. As seen most clearly byreference to FIG. 2, which shows a second form of the invention wherebythe cantilevered members are oriented in another arrangement, each ofthe cantilevered members 20 has a first end 21, and a distal second end22. Mounted on the second end 22 is an environmentally sensitive surface23 which when exposed to an environmental factor may subsequentlyexperience a change in thickness; damping; stiffness; Young's modulusdimensional; material properties such as elasticity, for example and/orcombinations thereof. While only a small region of the distal end iscovered by the environmentally sensitive surface or coating, it shouldbe recognized that the entire surface area between the first and secondends 21, and 22 may be covered by the environmentally sensitive surfaces23. The cantilever member 20 is held in spaced relation relative to theupwardly facing surface 15 by a support member 30. As seen in FIGS. 1-4,for example, the plurality of acoustic devices 20 can be positioned inan array 40 as seen in FIGS. 1 and 2 for example, and which are operableto respond to different environmental factors as will be discussed ingreater detail hereinafter. In the arrangement as seen in FIG. 1 andfollowing, it should be understood that the first, second and thirdforms of the invention 11, 12 and 13, respectively, each include atleast one acoustic device 20 which has a characteristic resonantvibrational frequency, and mode pattern, when exposed to a source ofacoustic energy and which is generally indicated by the numeral 50.Further, when exposed or following exposure to an environmental factor,as will be described below, these same acoustic devices as understood inthe first, second and third forms of the invention 11, 12 and 13 producea different resonant vibrational frequency and/or mode pattern whensubsequently exposed to the same source of acoustic energy 50. This isillustrated most clearly by a study of FIGS. 5, 6, 7A and 7B,respectively.

In the arrangement as seen with respect to the first, second and thirdforms of the invention 11, 12 and 13 which are generally graphicallydepicted, it will be appreciated that the acoustic device selected, suchas 20, may be selected from the group which includes quartz crystalmicrobalances; surface acoustic wave transducers; and thin film bulk,linear and/or torsional acoustic resonators. Yet further, theenvironmental factor that the first, second and third forms of theinvention 11, 12, and 13 can detect are selected from the non-limitinggroup comprising biological; chemical; thermal; acoustic;electromagnetic and/or combinations thereof. In some instances, theacoustic device as shown in the several forms of the invention, mayincrease in mass following exposure to the environmental factor. On theother hand, various forms of the invention may be designed such that theacoustic device may experience a decrease in mass following exposure tothe environmental factor(s) discussed above. In any event, the acousticdevice selected, as may be provided in the first, second and third forms11, 12 and 13, experience physical changes following the exposure to theenvironmental factor. These changes may result, as noted above, inchanges to the mass, thickness; damping; stiffness; Young's modulus ofthe acoustic device and/or combinations thereof. As noted, when theacoustic device is subsequently exposed to the same source of acousticenergy it produces a different resonant vibrational frequency or modepattern which can be visually detected, and which conclusivelydemonstrates the presence of the environmental factor. This is clearlyillustrated in FIGS. 7A and 7B, for example. This arrangement can alsobe calibrated to indicate the quantity of the environmental factor whichwas exposed to apparatus 10.

In the arrangement as seen in FIG. 1 and FIG. 5, for example, it shouldbe understood that the several different acoustic devices as may be seenin the first, second and third forms of the invention 11, 12 and 13 maybe placed into an array 40, and wherein the plurality of acousticdevices are operable to respond to different environmental factors whichcan be read or otherwise detected substantially simultaneously. Asshould be understood, the source of acoustic energy 50 may be providedor otherwise supplied to the first, second and third forms of theinvention 11, 12 and 13 at a single frequency, or may be provided at aplurality of frequencies. Still further, the source of acoustic energy50 may be supplied by the ambient environment. Additionally, it shouldbe understood that the environmentally sensitive surface 23 may comprisea commercially produced molecularly imprinted polymer 24 which has anaffinity for and/or which bonds to a specific organic or inorganicchemical, microorganism, or biological material. In the arrangements asillustrated, the source of acoustic energy 50 may be derived from anenergy source which is selected from the non-limiting group including,but not limited to, electrostatic; capacitive; thermal; optical;acoustic; magnetic; piezoelectric; mechanical; and/or combinationsthereof. In the arrangement as shown, generally any source of acousticenergy 50 may be useful in the practice of the present invention.

As seen in FIG. 1, the first form of the invention 11 includes aplurality of these acoustic devices, here illustrated as thecantilevered members 20, which are positioned in consecutive linearrows. The individual cantilevered members 20 may be rendered operable todetect a single environmental factor or multiple environmental factorsall from the same array 40.

As will be discussed below, and by reference to FIGS. 7A and 7B, itshould be understood that the sensors may be disposed in a side-by-sideorientation and which are individually operable to respond to differentenvironmental factors. Referring now to FIG. 4, the third form 13 of thesensor apparatus 10 is shown, and which includes groups of acousticsensors 60 which again, like the first and second forms 11 and 12 of theinvention 10, are operable to detect various environmental factors thatmight be exposed to same. The groups of acoustic sensors 60 arepositioned on a supporting substrate 61, and are made up of individualacoustic sensors 62 which are disposed in spaced relationship one to theother as seen in FIG. 5. As shown therein, the individual acousticsensors 62 have a first end 63 and an opposite second end 64 which areaffixed to the supporting substrate 61. The individual acoustic sensorsfurther have an upwardly facing, and deformable surface 65 which hasbeen treated or otherwise coated, or supplied with an environmentallysensitive surface 66 such as a molecular imprinted polymers as earlierdiscussed with respect to the first form of the invention 11. As seen inFIGS. 5, 6, 7A and 7B, the groups of acoustic sensors 60 are exposed tothe environmental factors as earlier described and they are operable tochange their acoustic characteristics similar to that which wasdescribed with respect to the first form of the invention 11, that is,once exposed to the environmental factor they produce a differentresonant vibrational frequency and/or mode pattern when exposed to thesame source of acoustic energy such as 50. As should be understood, anassembly for transmitting the given acoustic energy to the acousticdevice 51 is provided and is only generally illustrated in FIG. 1. Itwill be seen by reference to FIG. 6, that the plurality of acousticsensors 60, as illustrated therein, have been previously exposed to anenvironmental factor which has caused the mass of the individualacoustic sensors 62 to change thereby deforming the upwardly facingsurface 65. This results in a change in the acoustic characteristics ofthese same devices once they are exposed to a source of acoustic energysuch as 50.

Referring now to FIG. 7A, individual groups of acoustic sensors 60 areshown, and which have been rendered operable to detect a selectedenvironmental factor. FIG. 7A depicts an actual mode pattern which isdisplayed from pairs of micromachined vibratory think film bulkresonator structures when these same acoustic devices are exposed to asource of acoustic energy 50 which has a frequency of 21.006467 MHz, andprior to the exposure of the acoustic devices 60 to the selectedenvironmental factor. Referring now to FIG. 7B, the same groups ofacoustic sensors 60, are shown, and which illustrate the mode pattern ofthe same groups of acoustic sensors 60 following exposure to theselected environmental factor, and when exposed to acoustic energy 50having a different frequency of about 21.006200 MHz. As can be seen, thechange in the mode pattern as illustrated by a comparison of FIGS. 7Aand 7B demonstrates that the groups of sensors 60 have been exposed tothe selected environmental factor.

FIGS. 2 and 3 show the second form 12 of the sensor apparatus 10 andwhich includes a plurality of acoustic devices, as illustrated, andwhich include various cantilevered members generally indicated by thenumeral 20. As best seen by a study of FIG. 2, the sensor apparatus 10includes an assembly 70 for imaging an acoustic device, such as 20,following the exposure of the acoustic device to the environmentalfactor, as earlier described, and while the acoustic device is beingexposed to the source of acoustic energy 50 to determine the resonantfrequency and/or modal pattern of the acoustic devices involved. Theassembly for imaging the acoustic devices 70 produces a visiblydiscernible image of mode pattern of the respective acoustic devices asseen most clearly by reference to FIGS. 7A and 7B, respectively. Theassembly for imaging an acoustic device 70 following the exposure of theacoustic device(s) to the environmental factor is shown in a greatlysimplified arrangement. Other devices which will work with equal successare those shown in U.S. Pat. No. 6,836,336, 6,134,006, 6,175,411 and6,486,962, the teachings of which are all incorporated by referenceherein. For ease of illustration, however, the assembly for imaging theacoustic device 70 generally includes a digital camera 71 or other videodevice which is capable of forming a discernible video image of therespective acoustic devices from coherent light which is directed at andreflected from the acoustic device 20 (FIGS. 7A and 7B). The digitalcamera or video device 71 is operably coupled with a camera lens whichis generally indicated by the numeral 72. Positioned in spaced relationrelative to the camera lens is an imaging lens 73. Further, a laser 74is positioned in spaced relation therebetween the digital camera 71, andthe imaging lens 73. The laser, in the present arrangement, is anon-contacting, coherent light emitting device which directs a beam oflight, as will be discussed below, at the plurality of vibratoryacoustic devices 20. The imaging device 70 further includes a beamsplitter 80, which is positioned in spaced relation relative to thelaser 74. Still further, first and second reflecting mirrors 81 and 82are provided to direct the emitted beam of light along a given course oftravel, as will be discussed below. The imaging assembly 70 furtherincludes a reference beam modulator 83. Additionally, a photorefractivematerial 84 is provided, and which is generally indicated by the numeral84.

As seen in FIG. 2, it is understood that the laser 74 produces a firstobject light beam 90, and a second reference light beam which isgenerally indicated by the numeral 100. In the arrangement as seen inFIG. 2, the imaging lens 73 is configured to focus the object beam 90,following reflection from the acoustic devices 20, which are in anarray, onto a desired location of the photorefractive material 84. Theimaging lens 73 has a conventional design presently understood in theart. In the arrangement as shown, and upon being reflected off theplurality of cantilevered members 20, the object beam 90 has beenimpressed with information defining the given vibrational displacementamplitude, and vibrational phase of the plurality of acoustic sensors 20which are shown in that view. The object beam 90 is combined tointerfere with the reference beam 100, and which takes place within thephotorefractive material 84 by way of a two-wave anisotropicself-diffraction, with or without polarization rotation. An equivalentarrangement using a four wave anisotropic self diffraction could also beemployed with equal success. In the arrangement as seen in FIG. 2, theobject and reference beams 90 and 100 are mutually coherent so as tointerfere within the photorefractive material 84. The reference beammodulator 83 operates on reference beam 100 to produce a phase modulatedreference beam. The phase modulated reference beam and the reflectedobject beam 90 interfere within and pass through the photorefractivematerial 84 so as to create a space charged field having a magnitudewhich is directly proportional to the vibration displacement. The spacecharge field produces an index of refraction grating by theelectro-optic effect which contains information of the vibration stateof the plurality of acoustic devices or cantilevered members 20 as shownin FIG. 4. The photorefractive material 84 has a given response timewherein the induced grating within the photorefractive substance 84passes the reflected object beam 90, and reference beam 100. Object beam90, and reference beam 100 interfere within the photorefractive material84 to create a space charged field and resulting induced grating whichdevelops within the response time of the photorefractive material 84. Inthis regard, the object beam 90 is reflected off of the vibratingacoustic devices or cantilevered members 20 having a vibrationdisplacement amplitude and a vibration phase. The photorefractivematerial 84 passes the reflected object beam 90 and the reference beam100 such that their interference therein creates a spaced charged fieldinduced grating having a diffraction efficiency which is directlyproportional to the vibration displacement for small amplitudes. Thisdisplacement of the acoustic devices or cantilevered members 20 which isinduced by the acoustic energy 50 is then captured as a digital videoimage in the digital camera or video device 71 which is provided. Theresults are seen in FIG. 7A and 7B. As illustrated in FIG. 2, it will beseen that the assembly for imaging the acoustic device 70 is operable toimage a plurality of acoustic devices 20 substantially simultaneouslyand without the shortcomings attendant with the earlier prior artpractices which have been described earlier in this application.

Operation

The operation of the described embodiment of the present invention isbelieved to be readily apparent and is briefly summarized at this point.

As seen in the various drawings, the sensor apparatus 10 of the presentinvention includes an acoustic device, such as 20 or 60, which has acharacteristic resonant vibrational frequency and mode pattern whenexposed to a source of acoustic energy 50. Still further, the source ofacoustic energy 50 has a given frequency which is supplied to theacoustic devices noted. In addition to the foregoing, an assembly forimaging the acoustic device 70 is provided. The imaging device isoperable to determine the resonant frequency and/or modal pattern of theacoustic device 60 when the acoustic device is exposed to the source ofacoustic energy 50. As seen in the drawings, a plurality of acousticdevices 20 or 60 may be deployed in an array 40. As seen in FIG. 2, theassembly for imaging the acoustic device 70 may image each of theplurality of acoustic devices substantially simultaneously. As earlierdiscussed, the source of acoustic energy 50 may be a separate source, ormay, in the alternative, be provided by the ambient environment. Asillustrated, the acoustic device 20 has a surface area 22, 65 which maybe treated to bond to a specific chemical or biological material orotherwise react to another environmental factor, which may be physical,material or anything of whatever nature which is in the environment. Forexample, when a biological material bonds to same, the acoustic device,such as 20, experiences a change in its physical characteristics (anincreasing mass) and which, at least in part, influences an acousticresponse of the acoustic device 20. The change in the acoustic responsemay include, at least in part, a resulting different resonantvibrational frequency and/or mode when exposed to the source of acousticenergy 50. As earlier discussed, the changes in the physicalcharacteristics of the acoustic device 20, 60 which effects the acousticresponse of the acoustic device relates to a change in mass; thickness;stiffness; damping; Young's Modulus, dimension, material properties suchas elasticity, for example, and/or combinations thereof. The surfacearea of the acoustic device may mount, for example, in one form, amolecularly imprinted polymer which has an affinity for, and/or bonds tothe specific chemical or biological materials which comprise, at leastin part, the environmental factor which is to be detected. As earlierdiscussed, the source of acoustic energy may be derived from nearly anyavailable source of acoustic energy, such as, for example,electrostatic; capacitive; thermal; optical; acoustic; magnetic;piezoelectric; mechanical and/or combinations thereof. In the inventionas shown, an assembly for imaging the acoustic device 70 is provided,and which includes, without limitation, a non-contacting coherent lightemitting device, such as the laser 74, which directs a beam of light 90at the plurality of vibrating acoustic devices 20, and which isreflected from same; and a photorefractive material 84 which couldconceivably be incorporated into a dynamic photorefractive holographicinterferometer. Further, the imaging assembly 70 includes a videoassembly which may comprise a digital camera 71 for capturing thereflected light 90, and which produces a video image of the vibrationalmovements of each of the acoustic devices 20. As shown in FIG. 2, theassembly for imaging the acoustic device 70 is not operably coupled withthe respective acoustic devices 20. Still further, the several acousticdevices 20 may be vibrated by the source of acoustic energy 50 at asingle resonant frequency, at multiple frequencies and/or which is movedor otherwise swept through a range of frequencies, depending upon thecircumstances. In the present invention 10, the plurality of acousticdevices are vibrated by a source of acoustic energy 50 at a resonantfrequency which lies within a range of about 100 Hz to about 5 GHz. Asseen in the various drawings, the surface area of any array 40 istypically less than about 100 square millimeters, although it isconceivable that larger arrays could be constructed.

In the arrangement as shown, the plurality of acoustic devices 20, 60 asseen in the various forms of the invention 11, 12 and 13 has anintrinsic response to an environmental factor, as earlier described,which results in a different resonant vibrational frequency and/or modewhen the acoustic device is exposed to the acoustic energy 50.

In the drawings, a method for detecting an environmental factor isshown, and which includes the steps of providing an acoustic device 20,60 having an acoustic property which includes a characteristic resonantvibrational frequency, and mode pattern, when exposed to acoustic energy50. The method further includes a step of exposing the acoustic device20, 60 to an environment which has an environmental factor to bedetected, and wherein the acoustic property and/or resulting acousticresponse of the acoustic device 20, 60 changes following the exposure ofthe acoustic device to the environmental factor. The method fordetecting an environmental factor further includes the step of supplyinga source of acoustic energy 50 to the acoustic device, and a furtherstep of imaging the acoustic device 70 following the exposure of theacoustic device to the environmental factor and while the supplying thesource of acoustic energy 50 to the acoustic device. The methodology ofthe present invention further includes a step of determining whether theresonant frequency and/or mode pattern of the acoustic device 20, 60 hasbeen changed as a result of exposure to the environmental factor. Asearlier described, the step of providing the acoustic device 20, 60 mayfurther comprise a step of providing a plurality of acoustic devices,and arranging the plurality of acoustic devices in an array 40. Asearlier noted, the environmental factor to be detected may comprise aplurality of different environmental factors which are selected from thegroup comprising biological; chemical; physical; material; thermal;acoustic; electromagnetic and/or combinations thereof. In thearrangements as illustrated, the method for imaging the acoustic device70 further comprises the steps of directing and reflecting a beam ofcoherent light 90 off of the acoustic device 20, 60; and capturing avideo image from a video device 71 of the vibrational movement of theseveral acoustic devices 20, 60 from the captured coherent light. In thearrangements as shown, the step of imaging the acoustic device furthercomprises imaging the plurality of acoustic devices substantiallysimultaneously.

Therefore, it will be seen, that the present invention provides aconvenient means whereby a plurality of environmental factors can beeasily detected, and readily read or identified from a micro-sensorarray which is relatively small in size, and convenient to use. Thepresent sensor apparatus 10 can be used in a wide range of commercialand military applications and provides a convenient means for rapidlydetecting possibly adverse environmental factors in a manner notpossible heretofore. Still further, the present invention offers a novelmethodology of reading arrays of variously designed sensors which areresponsive to all manner of sources of vibrational or acoustic energy,and which have been rendered useful in detecting any desiredenvironmental factor as discussed above.

In compliance with the statute, the invention has been described inlanguage more or less specific as to structural and methodical features.It is to be understood, however, that the invention is not limited tothe specific features shown and described, since the means hereindisclosed comprise preferred forms of putting the invention into effect.The invention is, therefore, claimed in any of its forms ormodifications within the proper scope of the appended claimsappropriately interpreted in accordance with the doctrine ofequivalents.

1. A sensor apparatus, comprising: an acoustic device which has acharacteristic resonant vibrational frequency and mode pattern whenexposed to a source of acoustic energy, and which further, when exposedto an environmental factor, produces a different resonant vibrationalfrequency and/or mode pattern when exposed to the same source ofacoustic energy.
 2. A sensor apparatus as claimed in claim 1, andwherein the acoustic device is selected from the group which includesquartz crystal microbalances; surface acoustic wave transducers; andthin film bulk linear and/or torsional acoustic resonators.
 3. A sensorapparatus as claimed in claim 1, and wherein the environmental factor isselected from the group comprising biological, chemical; physical;material; thermal; acoustic; electromagnetic and/or combinationsthereof.
 4. A sensor apparatus as claimed in claim 1, and wherein theacoustic device experiences an increase in mass following exposure tothe environmental factor.
 5. A sensor apparatus as claimed in claim 1,and wherein the acoustic device experiences a decrease in mass followingexposure to the environmental factor.
 6. A sensor apparatus as claimedin claim 1, and wherein the acoustic device has acoustic propertieswhich change following exposure of the acoustic device to theenvironmental factor.
 7. A sensor apparatus as claimed in claim 1, andwherein the acoustic device experiences a change in mass; thickness;damping; stiffness; Young's Modulus dimension, material properties,and/or combinations thereof when exposed to the environmental factor. 8.A sensor apparatus as claimed in claim 1, and further comprising: anassembly for imaging the acoustic device following the exposure of theacoustic device to the environmental factor, and while the acousticdevice is being exposed to the source of acoustic energy to determinethe resonant frequency and/or modal pattern of the acoustic device.
 9. Asensor apparatus as claimed in claim 1, and wherein the source ofacoustic energy is provided at a single frequency.
 10. A sensorapparatus as claimed in claim 1, and wherein the source of acousticenergy is provided at a plurality of frequencies.
 11. A sensor apparatusas claimed in claim 1, and wherein the source of acoustic energy isswept through the plurality of frequencies.
 12. A sensor apparatus asclaimed in claim 1, and wherein a plurality of acoustic devices areplaced in an array, and wherein the plurality of acoustic devices areoperable to respond to different environmental factors.
 13. A sensorapparatus, comprising: an acoustic device which has a characteristicresonant vibrational frequency and mode pattern when exposed to acousticenergy; an assembly for transmitting acoustic energy to the acousticdevice; a source of acoustic energy of a given frequency which issupplied to the acoustic device; and an assembly for imaging theacoustic device to determine the resonant vibrational frequency and/ormodal pattern of the acoustic device when the acoustic device is exposedto the source of acoustic energy.
 14. A sensor apparatus as claimed inclaim 13, and wherein a plurality of acoustic devices are deployed in anarray, and wherein the assembly for imaging the acoustic device imageseach of the plurality of acoustic devices substantially simultaneously.15. A sensor apparatus as claimed in claim 13, and wherein the source ofacoustic energy is supplied by an ambient environment, and wherein theacoustic device responds to the acoustic energy provided by the ambientenvironment, and has a resulting resonant vibrational frequency and/ormode pattern corresponding to the ambient acoustic energy.
 16. A sensorapparatus as claimed in claim 12, and wherein the acoustic device has asurface area which has been treated to bond to a specific chemical orbiological material, and wherein the surface area when exposed to thespecific chemical or biological material bonds to same, and experiencesa change in its physical characteristics and which, at least in part,influences an acoustic response of the acoustic device, and wherein thechange in the acoustic response includes, at least in part, a resultingdifferent resonant vibrational frequency and/or mode when exposed to thesource of acoustic energy.
 17. A sensor apparatus as claimed in claim16, and wherein the change in the physical characteristics of theacoustic device which effects the acoustic response of the acousticdevice relates to a change in physical and/or material properties suchas mass; thickness; stiffness; damping; Young's Modulus and/orcombinations thereof.
 18. A sensor apparatus as claimed in claim 16, andwherein the surface area of the acoustic device mounts a molecularlyimprinted polymer and/or analyte binding material which has an affinityfor, and/or bonds to the specific chemical or biological material.
 19. Asensor apparatus as claimed in claim 13, and wherein the acoustic deviceis selected from the group which includes, but is not limited to, quartzcrystal microbalances; surface acoustic wave transducers; and thin filmbulk linear and/or torsional acoustic resonators.
 20. A sensor apparatusas claimed in claim 13, and wherein the source of acoustic energy isderived from an energy source which is selected from the group whichincludes, but is not limited to, electrostatic; capacitive; thermal;optical; acoustic; magnetic; piezoelectric; mechanical and/orcombinations thereof.
 21. A sensor apparatus as claimed in claim 13, andwherein the assembly for imaging the acoustic device further comprises:a non-contacting coherent light emitting device which directs a beam oflight at the plurality of vibrating acoustic devices, and which isreflected from same; and a dynamic photorefractive holographicinterferometer, and video assembly for capturing the reflected light,and which produces a video image of the vibrational mode pattern andmovement of each of the acoustic devices, and wherein the non-contactingcoherent light emitting device, dynamic photorefractive interferometer,and video assembly are not operably coupled to the acoustic device. 22.A sensor apparatus as claimed in claim 13, and wherein the acousticdevice is vibrated by the source of acoustic energy at a single resonantfrequency.
 23. A sensor apparatus as claimed in claim 13, and whereinthe acoustic device is vibrated by the source of acoustic energy atdifferent resonant frequencies.
 24. A sensor apparatus as claimed inclaim 23, and wherein the acoustic device is swept through a range offrequencies of acoustic energy.
 25. A sensor apparatus as claimed inclaim 13, and wherein the acoustic device is vibrated by the source ofacoustic energy at a resonant frequency which lies within a range ofabout 100 Hz to about 5 GHz .
 26. A sensor apparatus as claimed in claim13, and wherein a plurality of acoustic devices are arranged in anarray, and wherein the respective acoustic devices each have a givenmass, and a surface area which is capable of bonding to a chemicaland/or biological material, and wherein the surface area of the arraymay be less than about 100 square millimeters.
 27. A sensor apparatus asclaimed in claim 13, and wherein the acoustic device has an intrinsicresponse to an environmental factor which results in a differentresonant vibrational frequency and/or mode when the acoustic device isexposed to the acoustic energy.
 28. A sensor apparatus as claimed inclaim 27, and wherein the acoustic device has a surface area which hasbeen treated to respond to some ambient environmental factor, andwherein the acoustic device when exposed to the ambient environmentalfactor produces a different resonant vibrational frequency and/or modewhen exposed to the source of acoustic energy.
 29. A sensor apparatus asclaimed in claim 28, and wherein the environmental factor is selectedfrom the group comprising physical; material; biological; chemical;thermal; acoustic; electromagnetic and/or combinations thereof.
 30. Amethod for detecting an environmental factor, comprising: providing anacoustic device having an acoustic property which includes acharacteristic resonant vibrational frequency and mode pattern whenexposed to acoustic energy; exposing the acoustic device to anenvironment which has an environmental factor to be detected, andwherein the acoustic property of the acoustic device changes followingthe exposure of the acoustic device to the environmental factor;supplying a source of acoustic energy to the acoustic device; imagingthe acoustic device following exposure of the acoustic device to theenvironmental factor and while supplying the source of acoustic energyto the acoustic device; and determining whether the resonant frequencyand mode pattern of the acoustic device has changed as a result ofexposure to the environmental factor.
 31. A method as claimed in claim30, and wherein the step of providing the acoustic device furthercomprises providing a plurality of acoustic devices and arranging theplurality of acoustic devices in an array, and wherein the environmentalfactor to be detected further comprises a plurality of differentenvironmental factors.
 32. A method as claimed in 30, and wherein thechange in the acoustic property is caused by a change in a physical ormaterial property, such as the mass; thickness, stiffness damping;and/or Young's modulus of the acoustic device.
 33. A method as claimedin claim 30, and wherein the environmental factor to be detectedcomprises physical; material; biological; chemical; thermal; acoustic;electromagnetic and/or combinations thereof.
 34. A method as claimed inclaim 28, and wherein the step of supplying a source of acoustic energyto the acoustic device further comprises providing a plurality offrequencies of acoustic energy in a range of about 100 Hz to about 5 GHzto the acoustic device.
 35. A method as claimed in claim 30, and whereinthe step of imaging the acoustic device further comprises: directing andreflecting a beam of coherent light off of the acoustic device; andcapturing the reflected coherent light, and producing a video image ofthe vibrational movement of the acoustic device from the capturedcoherent light.
 36. A method as claimed in claim 31, and wherein thestep of imaging the acoustic device further comprises imaging theplurality of acoustic devices substantially simultaneously.